#include<stdio.h>
#define PI 3.141592654
int main()
{
    char info[]="hello world!!!";   //C中没有字符串变量，用字符数组来表示
    float s;
    int a,b,r;
    a=123;b=12345;
    r=3;
    s=PI*r*r;       //求圆的面积
    printf("半径r为%d，圆的面积为%5.2f\n", r, s);
    printf("*%d* *%d*\n", a, b);
    printf("*%5d* *%4d*\n", a, b);
    printf("*%-5d* *%-4d*\n", a, b);
    printf("显示原始字符串%s\n", info);
    printf("显示前五个字符，右对齐*%8.5s*\n");
    printf("显示前五个字符，左对齐*%-8.5s*\n");
    return 0;
}